Networking of high-performance computers has become the focus of much attention in the data communications industry. Performance improvements in processors and peripherals, along with the move to distributed architectures such as client/server configurations, have spawned increasingly data-intensive and high-speed network applications, such as medical imaging, multimedia, and scientific visualization.
One protocol that has been developed to provide the necessary communications capacity is the Fibre Channel (FC) protocol. A single FC link can carry data at rates exceeding 1 gigabit per second (Gb/s) in both directions simultaneously. The FC protocol defines standard media and signaling conventions for transporting data in a serial fashion. It also provides an error correcting channel code and a frame structure for transporting the data. Further, the FC protocol sets out a buffer-credit-based flow control methodology, and creates some common services (e.g. fabric controller, name server). The FC protocol can be applied to various network topologies including point-to-point, ring, and switched fabric. Further details regarding the FC protocol can be found online at the Fibre Channel website.
FC networks can grow quite large. The protocol allows for nearly 224 (over 16 million) node ports within a single fabric (a FC network includes one or more FC fabrics). Each node port supports one FC device. As larger networks are implemented (e.g., more than about eight switches), various unforeseen weaknesses in the FC protocol become evident. For example, the amount of network traffic necessary to support and use the name server grows as the square of the number of devices attached to the fabric, and this traffic can at times severely impair the performance of the network. It would be desirable to eliminate or mitigate the adverse effects of this traffic, thereby improving the speed, efficiency, and reliability of larger networks.